WHITE RIVER JUNCTION — A Cabot woman and her boyfriend were charged with heroin trafficking Wednesday after a 2 a.m. traffic stop on Interstate 91 led to the discovery of drugs in the spare tire of their car, police said.

Samantha Eldred, 22, of Cabot, pleaded innocent in White River Junction criminal court to a felony count of heroin trafficking, which carries a maximum sentence of 30 years. She was released from court on a curfew and other conditions.

Eldred’s boyfriend, Jose Rodriguez, 20, pleaded innocent to the same charge but was jailed for lack of $25,000 bail.

The third person arrested was Juan Rodriguez Jr., 25, who Eldred described as her “stepson” to police. He was also originally charged with trafficking, but a judge dropped the charge because he was in a second vehicle, not the one in which the drugs were found.

Vermont State Police Sgt. Michael Studin said the two vehicles were northbound on I-91 at about 1:30 a.m. Wednesday when he saw one of them had a large crack in the windshield.

Studin pulled over the car, a Chrysler 300, which was occupied by Jose Rodriguez and a small child. The sergeant said the other car, a Honda Accord, accelerated past the stopped vehicle and appeared to be trying to draw him away from the Chrysler.

Studin said he had another trooper stop the Honda, driven by Juan Rodriguez and also carrying Eldred.

Eldred told police they had an eighth of an ounce of marijuana hidden in the console of the car, Studin said. After Eldred consented to a search of the vehicle, Studin said, he and Trooper Eric Vitali found a “large ball-shaped object wrapped in black electrical tape” inside the deflated spare tire.

When the object was cut open at the police barracks, he said, it contained 740 bags of heroin stamped with the street brand “Sniper.” There were also nearly 4 grams of powdered cocaine and 30 grams of marijuana, according to the police report.